I also agree with three comments before me.
With that large of air control butterfly valve right behind the engine filter it will be tricky to control air flow, if you move it a little open it could be to much air flow. Is it hooked up to a throttle cable be control from the driver seat?
When you are running on char gas, with the gas out of the carburetor go ahead and advance your timing it should smooth out the idle and maybe the rpms will pick up a little. It is real handy to beable to do this from the cab or drivers seat. But I know people who just set the truck up to run on charcoal all the time and never on petroleum fuel.
On my charcoal unit I have 4 socks filters after a cyclone filter. Your filter sock could be the problem, like Joni said you need more square inches surface space if it is caking up fast.
It have to breath with out to high of a vaccum. It would be like restricting the air on the carburetor at idle. The engine will not keep running.
I see no problem with the length of the engine intake filter to the carburetor it is about the same as mine.
Bob
The filter material is pretty loose. I can see pinholes of daylight through it when it’s clean.
I’ll try a short run with no filter to see how it does. I have more of this material so I can make a wider sock filter if need be.
I’m wondering if closing off one end of the flute nozzle would let you get more velocity into your reaction. Seems like it would take a lot of engine to pull though that much open area of a fairly large diameter open ended nozzle.
I did try that, and I didn’t really see any difference under load. It goes to 5 .5" sized holes so there is a sort of bottleneck to how open the flutes are.
I really had a stroke of good luck with the chipper I ordered. It’s shipping from my state and eBay estimates it will be delivered tomorrow. Wish that the seller had a physical store or I would have just driven there 
I need to look for one of those long magnet bars so i can catch nails from the charcoal before I grind it.
Just use an old blown out speaker mounted on a piece of EMT.
Good to know.
So when the chipper gets here I will make a fresh batch of much smaller sized fuel grade char, and repeat the test. This includes inspecting the charcoal in the reactor itself and reducing the size of that as well.
The batch inside the reactor I think a few nails slipped in because I would occasionally hear a loud sizzling with some sparking falling down through the flute holes so I’m going to take photos of the flutes from the inside of the reactor to check for any damage.
And I use a magnet for lifting plates. It has a handle on it, so it is easy to remove the nails from the magnet.
I got the chipper today! Tested it out on some branches first. Shreds it down to very small sizes. Probably too small for a gasifier I’m sure it would be Bridge City. But it grinds down the charcoal pretty well. I found that hardwood charcoal doesn’t make as much dust and makes bigger pieces when chipped.
This specific Sunjoe chipper has an internal 17:1 gear ratio already so it is slower with more torque than the older ones.
I’m going to build two different classifying ramps. One is to filter out the smaller stuff to save, and leave only the pieces bigger than 3/4" to grind down.
And the other ramp to remove anything smaller than 1/8".
Maybe I’ll make a trommel out of a bucket for sizing out the biggest pieces. Then my ramp to get dust out.
Oh yes THAT is engine grade charcoal! Anctious to see how this performs
Cody,
Does your chipper create a lot of fines (less that 1/8 inch)? If that turns out to be a success, I may get one. Can you give details on your chipper?
I cant find a 1/8" sized screen but I’ll see if my old window screen will sort the dust out.
I think I get maybe 1/8 of the finished product as dust.
I went on eBay and looked for an electric woodchipper. This isn’t the same color as the one I got but it has the same gear ratio and amperage as mine. Same brand and eBay seller.
Sun Joe Electric Wood Chipper | 17:1 Reduction | 15 Amp | Certified Refurbished | eBay
Hardly worth diddly for wood unless it’s twigs and very thin branches. Might be good to make filter media out of.
The blades are removable so maybe I could modify the blades to sit lower and get bigger pieces.
I’ll try to weigh out a pound of charcoal, grind it all and weigh how much finished product I get compared to dust.
Ok so out of one pound of charcoal, processed I lost 3 or so ounces to dust.
I’m going to attempt to crush char without the blades in place. See if I can get it just a bit more coarse.
Blades really don’t want to come out so I won’t push my luck.
Does that chipper have a universal (brush type) motor? If it does maybe a speed controller would slow it down enough to allow bigger pieces to slip through. 3 ounces per pound is not that bad though and the picture you showed looks good to me for engine fuel. Give it a try and keep lemons handy!
I’m not sure what kind of motor it is. The motor has a plastic dust cover over it so I’ll have to take it apart to check.
You can usually tell by listening to it. Brush type motors have a whine like a vacuum cleaner or skill saw. Induction motors are more quiet like bench grinders etc.